Frequently it is necessary to lift items which are floating or anchored in the water. For example, in areas of the world where it is anticipated that water will freeze, floating items such as boat lifts, rafts, floating docks and the like are removed from the water as winter approaches in order to avoid damage from ice. Similarly, it may become necessary to maintain floating structures which are anchored to the bottom, such as buoys. Buoys are often located far from a shoreline and accessibly only by boat. In such a case, it is desirable to lift the buoy out of the water to perform maintenance operations, such as changing batteries, maintaining solar cells, painting markings and the like, thereby allowing the operator to remain in the boat while performing the maintenance operations. It would also be advantageous to be able to place the buoy on a stable platform which will make it easier to perform the maintenance operations.
There exist various machines for lifting and transporting heavy items, such as conventional land-based forklifts. Conventional forklifts may be effective in lifting items on land, but are not effective in moving waterborne items, such as floating docks, rafts, boats, boatlifts, buoys, and the like, unless such item is adjacent a dock or the shore. Then, the movement is typically limited to movement from adjacent a dock or the shore to a location on land, and the reverse. An example of such land-based lifting device is found in U.S. Patent Publication No. 2008-0095578 A1.
Cranes are another type of land based machines for lifting and transporting heavy items. However, cranes are not suitable for reaching waterborne items located a distance away from the shore or for transporting items over longer distances. Moreover, it may not be economical to employ a crane for lifting smaller items. Further, cranes typically require slings or other means to support the load being lifted, which may be difficult to attach to a number of structures.
There also exist various water-based or amphibious vessels which include implements for performing water related tasks, such as bulldozing, digging, dredging, and pushing other vessels. See, for example, U.S. Pat. Nos. 2,853,812, 6,273,767, 4,831,751, and 4,534,738. However, these water-based or amphibious vessels are not suitable for carefully lifting, manipulating, and transporting waterborne items.
Accordingly, there is a need for more easily and inexpensively lifting, manipulating, and transporting waterborne items.